T7700 mostly running at only 1.2 GHz

[phenyl]

Hi,

as I wrote in http://forum.thinkpads.com/viewtopic.php?f=29&t=81511 , I got a new fan-unit for my T61 (7658-11J) due to noise and the intermittent 'fan error' on book. As I had to open the laptop anyways, I also ordered a Core2Duo T7700 with 2.4 GHz and 4 MB cache to replace the T7100/1.8GHz/2MB.
I plugged it in and reassembled the machine with the new fan.

In order to test the cpu to verify that everything is ok, I started running an electronic structure calculation under Linux on both cores. The machine started out at 2.4 GHz and then reduced the clock frequency to 1.2 GHz after about one minute.
The laptop is plugged into the wall outlet and a battery is present. If I remember correctly, some thinkpads would not run at full speed without battery.

I checked the cpu-temperatures and they were not overly high, here the output from sensors:

Code: Select all

fan1:       3057 RPM
...
coretemp-isa-0000
Adapter: ISA adapter
Core 0:      +52.0°C  (high = +100.0°C, crit = +100.0°C)  

coretemp-isa-0001
Adapter: ISA adapter
Core 1:      +54.0°C  (high = +100.0°C, crit = +100.0°C)  

The T7100 never had Problems running at 1.8 GHz even under prolonged load.

When installing the fan, I payed attention that it was lying flat on the cpu and that the screws were all tightened the same; and it is running, as can be seen in the output above. I updated the bios to the newest version back in May or June, so the CPU should be supported flawlessly.

I would be grateful for any idea to get the full performance from my new processor.